Efforts to legalize marijuana are currently sweeping the nation, and the degree to which empirical scientific research is informing such policy change in unknown. Because future policy tends to build upon current policy, it is imperative that we understand how empirical scientific research is used in the public health policy decision process, i.e., the conditions under which science will inform policy making, and ways to facilitate policy makers? utilization of science in their policy making process. Our long-term objective is to contribute to the science of translation by using this case study to explain and predict the conditions under which research will be used to inform public health policy decisions. We will conduct a comparative analysis of four cases of the legalization of marijuana: legalization in Alaska and Oregon (autumn 2014), and defeated/failed legalization attempts in Ohio (autumn 2015) and New Mexico (2016). For each of these cases we will collect and analyze the written commentary, public hearing testimony, and media coverage of the proposed marijuana legalization. We will assemble the evidence submitted as commentary on the proposed marijuana legalization efforts, and analyze quality and quantity of the science. In addition, we will interview elected or appointed public officials who were involved participants in the policy arena regarding marijuana legalization in their state. We aim to discover the scientific research that effectively informed policy decisions regarding marijuana legalization, and how that scientific research is distinguished from research that failed to inform policy. Our specific aims are: (1) To identify research users, examining how public health policy makers define (what constitutes ?research?), acquire, interpret, and use scientific research; (2) To explore the social and political conditions under which scientific research will be used or adapted to inform public health policy; (3) To compare and contrast the relevant scientific research that was used to inform policy with the relevant scientific research with that that was not used; and, (4) To contribute to the science of translation by delineating the conditions under which policy makers will make decisions based on research findings, i.e., who makes for the best translators and how to create productive contexts for successful translation of research to policy. With a better understanding of what facilitates or hampers the uptake of scientific evidence regarding the health effects of marijuana use, we would know what makes the scientific evidence more valuable to public health policy makers.